GSTE is partitioned model checking

Verifying whether an ω-regular property is satisfied by a finite-state system is a core problem in model checking. Standard techniques build an automaton with the complementary language, compute its product with the system, and then check for emptiness. Generalized symbolic trajectory evaluation (GSTE) has been recently proposed as an alternative approach, extending the computationally efficient symbolic trajectory evaluation (STE) to general ω-regular properties. In this paper, we show that the GSTE algorithms are essentially a partitioned version of standard symbolic model-checking (SMC) algorithms, where the partitioning is driven by the property under verification. We export this technique of property-driven partitioning to SMC and show that it typically does speed up SMC algorithm

Parikh Automata over Infinite Words

Parikh automata extend finite automata by counters that can be tested for membership in a semilinear set, but only at the end of a run, thereby preserving many of the desirable algorithmic properties of finite automata. Here, we study the extension of the classical framework onto infinite inputs: We introduce reachability, safety, B\"uchi, and co-B\"uchi Parikh automata on infinite words and study expressiveness, closure properties, and the complexity of verification problems. We show that almost all classes of automata have pairwise incomparable expressiveness, both in the deterministic and the nondeterministic case; a result that sharply contrasts with the well-known hierarchy in the $\omega$-regular setting. Furthermore, emptiness is shown decidable for Parikh automata with reachability or B\"uchi acceptance, but undecidable for safety and co-B\"uchi acceptance. Most importantly, we show decidability of model checking with specifications given by deterministic Parikh automata with safety or co-B\"uchi acceptance, but also undecidability for all other types of automata. Finally, solving games is undecidable for all types

Containment for Rule-Based Ontology-Mediated Queries

Many efforts have been dedicated to identifying restrictions on ontologies expressed as tuple-generating dependencies (tgds), a.k.a. existential rules, that lead to the decidability for the problem of answering ontology-mediated queries (OMQs). This has given rise to three families of formalisms: guarded, non-recursive, and sticky sets of tgds. In this work, we study the containment problem for OMQs expressed in such formalisms, which is a key ingredient for solving static analysis tasks associated with them. Our main contribution is the development of specially tailored techniques for OMQ containment under the classes of tgds stated above. This enables us to obtain sharp complexity bounds for the problems at hand, which in turn allow us to delimitate its practical applicability. We also apply our techniques to pinpoint the complexity of problems associated with two emerging applications of OMQ containment: distribution over components and UCQ rewritability of OMQs

Regular Rooted Graph Grammars

In dieser Arbeit wir ein pragmatischer Ansatz zur Typisierung, statischen Analyse und Optimierung von Web-Anfragespachen, speziell Xcerpt, untersucht. Pragmatisch ist der Ansatz in dem Sinne, dass dem Benutzer keinerlei Einschränkungen aus Entscheidbarkeits- oder Effizienzgründen auf modellierbare Typen gestellt werden. Effizienz und Entscheidbarkeit werden stattdessen, falls nötig, durch Vergröberungen bei der Typprüfung erkauft. Eine Typsprache zur Typisierung von Graph-strukturierten Daten im Web wird eingeführt. Modellierbare Graphen sind so genannte gewurzelte Graphen, welche aus einem Spannbaum und Querreferenzen aufgebaut sind. Die Typsprache basiert auf reguläre Baum Grammatiken, welche um typisierte Referenzen erweitert wurde. Neben wie im Web mit XML üblichen geordneten strukturierten Daten, sind auch ungeordnete Daten, wie etwa in Xcerpt oder RDF üblich, modellierbar. Der dazu verwendete Ansatz---ungeordnete Interpretation Regulärer Ausdrücke---ist neu. Eine operationale Semantik für geordnete wie ungeordnete Typen wird auf Basis spezialisierter Baumautomaten und sog. Counting Constraints (welche wiederum auf presburgerarithmetische Ausdrücke) basieren. Es wird ferner statische Typ-Prüfung und -Inferenz von Xcerpt Anfrage- und Konstrukttermen, wie auch Optimierung von Xcerpt Anfragen auf Basis von Typinformation eingeführt.This thesis investigates a pragmatic approach to typing, static analysis and static optimization of Web query languages, in special the Web query language Xcerpt. The approach is pragmatic in the sense, that no restriction on the types are made for decidability or efficiency reasons, instead precision is given up if necessary. Pragmatics on the dynamic side means to use types not only to ensure validity of objects operating on, but also influencing query selection based on types. A typing language for typing of graph structured data on the Web is introduced. The Graphs in mind are based on spanning trees with references, the typing languages is based on regular tree grammars with typed reference extensions. Beside ordered data in the spirit of XML, unordered data (i.e. in the spirit of the Xcerpt data model or RDF) can be modelled using regular expressions under unordered interpretation – this approach is new. An operational semantics for ordered and unordered types is given based on specialized regular tree automata and counting constraints (them again based on Presburger arithmetic formulae). Static type checking of Xcerpt query and construct terms is introduced, as well as optimization of Xcerpt query terms based on schema information

Computer Aided Verification

This open access two-volume set LNCS 11561 and 11562 constitutes the refereed proceedings of the 31st International Conference on Computer Aided Verification, CAV 2019, held in New York City, USA, in July 2019. The 52 full papers presented together with 13 tool papers and 2 case studies, were carefully reviewed and selected from 258 submissions. The papers were organized in the following topical sections: Part I: automata and timed systems; security and hyperproperties; synthesis; model checking; cyber-physical systems and machine learning; probabilistic systems, runtime techniques; dynamical, hybrid, and reactive systems; Part II: logics, decision procedures; and solvers; numerical programs; verification; distributed systems and networks; verification and invariants; and concurrency

Foundations of Software Science and Computation Structures

This open access book constitutes the proceedings of the 22nd International Conference on Foundations of Software Science and Computational Structures, FOSSACS 2019, which took place in Prague, Czech Republic, in April 2019, held as part of the European Joint Conference on Theory and Practice of Software, ETAPS 2019. The 29 papers presented in this volume were carefully reviewed and selected from 85 submissions. They deal with foundational research with a clear significance for software science

Le problème de la valeur dans les jeux stochastiques

La théorie des jeux est un outils standard quand il s'agit de l'étude des systèmes réactifs. Ceci est une conséquence de la variété des modèle de jeux tant au niveau de l'interaction des joueurs qu'au niveau de l'information que chaque joueur possède.Dans cette thèse, on étudie le problème de la valeur pour des jeux où les joueurs possèdent une information parfaite, information partiel et aucune information. Dans le cas où les joueurs possèdent une information parfaite sur l'état du jeu,on étudie le problème de la valeur pour des jeux dont les objectifs sont des combinaisons booléennes d'objectifs qualitatifs et quantitatifs.Pour les jeux stochastiques à un joueur, on montre que les valeurs sont calculables en temps polynomiale et on montre que les stratégies optimalespeuvent être implementées avec une mémoire finie.On montre aussi que notre construction pour la conjonction de parité et de la moyenne positivepeut être étendue au cadre des jeux stochastiques à deux joueurs. Dans le cas où les joueurs ont une information partielle,on étudie le problème de la valeur pour la condition d'accessibilité.On montre que le calcul de l'ensemble des états à valeur 1 est un problème indécidable,on introduit une sous classe pour laquelle ce problème est décidable.Le problème de la valeur 1 pour cette sous classe est PSPACE-complet dansle cas de joueur aveugle et dans EXPTIME dans le cas de joueur avec observations partielles.Game theory proved to be very useful in the fieldof verification of open reactive systems. This is due to the widevariety of games' model that differ in the way players interactand the amount of information players have.In this thesis, we study the value problem forgames where players have full knowledge on their current configurationof the game, partial knowledge, and no knowledge.\\In the case where players have perfect information,we study the value problem for objectives that consist in combinationof qualitative and quantitative conditions.In the case of one player stochastic games, we show thatthe values are computable in polynomial time and show thatthe optimal strategies exist and can be implemented with finite memory.We also showed that our construction for parity and positive-average Markov decisionprocesses extends to the case of two-player stochastic games.\\In the case where the players have partial information,we study the value problem for reachability objectives.We show that computing the set of states with value 1 is an undecidableproblem and introduce a decidable subclass for the value 1 problem.This sub class is PSPACE-complete in the case of blind controllersand EXPTIME is the setting of games with partial observations.BORDEAUX1-Bib.electronique (335229901) / SudocSudocFranceF

Computer Aided Verification

This open access two-volume set LNCS 11561 and 11562 constitutes the refereed proceedings of the 31st International Conference on Computer Aided Verification, CAV 2019, held in New York City, USA, in July 2019. The 52 full papers presented together with 13 tool papers and 2 case studies, were carefully reviewed and selected from 258 submissions. The papers were organized in the following topical sections: Part I: automata and timed systems; security and hyperproperties; synthesis; model checking; cyber-physical systems and machine learning; probabilistic systems, runtime techniques; dynamical, hybrid, and reactive systems; Part II: logics, decision procedures; and solvers; numerical programs; verification; distributed systems and networks; verification and invariants; and concurrency